Dr. R. A. J. R. Sheeba

Ms. R. A. J. R. Sheeba, Research Scholar, Dept. of Physics,
The Madura College, Madurai – 625 011
Mobile: 98650 10464,
Email: [email protected]

Research Topic:

Preparation and physical characterization of silicon and germanium based diluted magnetic semiconductors

Date of Regis: 09.04.2010
Reg. No. P8372
Viva-Voce date: 11.12.2018

About the work:

DMS materials are very important due to the potential application in the field of electronics.   Some of the applications of DMS materials include spintronic devices such as, GMR read head, Magnetic sensors, MRAM (Magneto – resistance Random Access Memory), Spin Transistor, Spin-FET etc. In this doctoral work, silicon and germanium based diluted magnetic semiconductors (DMS) have been prepared and characterized for their structural properties, distribution of charges, magnetic properties and morphological nature.

DMS materials prepared:

  1. Ge1-xMnx (x = 0.04, 0.06, 0.10)
  2. Ge1-xVx (x = 0.03, 0.06, 0.09)
  3. Ge1-xCox (x = 0.03, 0.06, 0.09)
  4. Si1-xMnx (x = 0.02)
  5. Si1-xNix (x = 0.03, 0.06, 0.09, 0.12)

Rietveld method has been employed for the structural analysis and maximum entropy method (MEM) for the charge density analysis. Pair distribution function (PDF) has been used to analyze the local structure of the prepared materials and the magnetic behavior of the prepared materials has been analyzed using the measurements recorded using vibrating sample magnetometer (VSM). The morphological nature of the samples was studied using scanning electron microscopy (SEM).

List of Publications:

  1. Understanding electronic and magnetic transitions in ball milled diluted magnetic semiconductor Si1-xNix through experimental electron density distribution, R.A.J.R. Sheeba, S. Saravanakumar, S. Israel and R. Saravanan,                                                                                              Journal of Alloys and Compounds 728 (2017) 887 – 895, (Elsevier) (Impact Factor: 3.133)
  2. Signature of antiferromagnetism in entropy maximized charge density distribution of melt grown diluted magnetic semiconductor Ge1-xVx, R.A.J.R. Sheeba, R. Saravanan and L. John Berchmans,                                                                                                                                                Journal of Materials Science: Materials in Electronics 26 No. 6 (2015)3772 – 3780, (Springer) (Impact Factor: 2.019)
  3. Magnetic and charge derived properties of ball milled DMS:Si0.98Mn0.02       R.A.J.R. Sheeba, R. Saravanan and S. Sasikumar,                                                                                                              Physica B 426 (2013) 71–78, (Elsevier) (Impact Factor: 1.386),
  4. Magnetism in melt grown dilute magnetic semiconductor Ge1-xMnx from electron density, R.A.J.R. Sheeba, R. Saravanan and L. John Berchmans,                                                              Materials Science in semiconductor processing ,Vol. 15 (2012) 731–739, (Elsevier) (Impact Factor: 2.359)
  5. Comparison of electronic structure of as grown and solar grade silicon samples, R. Saravanan and R.A.J.R. Sheeba,                                                                                                                                  Semiconductors Vol. 46, No. 4 (2012) 440–446, (Springer) (Impact Factor: 0.641)
  6. A theoretical estimation of the charge density distribution in the diluted magnetic semiconductors of Si1-xMx and Ge1-xMx (M = V, Mn, Co),                                                            R.A.J.R. Sheeba, R. Saravanan and L. John Berchmans,                                                                            Materials Science Forum Vol. 699 (2012)167–183, (Trans Tech publications, Switzerland) (Impact Factor: 0.4)
  7. Analysis on insulator – metal transition in Yttrium doped LSMO from electron density distribution, S. Israel, S. Saravanakumar, R. Renuretson, R.A.J.R. Sheeba and R. Saravanan, Bulletin of Materials Science 35 (2012)111, (Springer) (Impact Factor: 0.870)
  8. The analysis on the rearrangement of charge density distribution in response to magnetic behavior in Mn doped SnO2 nanoparticles, S. Saravanakumar, M. Pattammal, S. Israel, R.A.J.R. Sheeba and R. Saravanan,                                                                                                                          Physica B 407 (2012) 302–310, (Elsevier)  (Impact Factor:  1.386)
  9. Analysis on experimental valence charge density in Germanium at RT and 200 K, S. Israel, K.S. Syed Ali, R.A.J.R. Sheeba and R. Saravanan, Journal of Physics and Chemistry of Solids 70 (2009) 1185–1194, (Elsevier) (Impact Factor: 2.059)
  10. X-ray analysis of charge density distribution in GaP at 296 and 200K using Multipole and MEM models, S. Israel, K.S. Syed Ali, R.A.J.R. Sheeba and R. Saravanan,                                              Chinese Journal of Physics 47, 3(2009) 378–400, (Elsevier) (Impact Factor:  0.692)